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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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A problem with a cd player
Hello
A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan |
#2
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A problem with a cd player
On 1/27/2009 11:23 PM Gaetan Mailloux spake thus:
A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. You don't need a schematic to figure out that many CD players have problems with CD-R discs. I've seen this on my own equipment. Depends on the type of CD-R discs *and* the recorder they were burned on. -- Made From Pears: Pretty good chance that the product is at least mostly pears. Made With Pears: Pretty good chance that pears will be detectable in the product. Contains Pears: One pear seed per multiple tons of product. (with apologies to Dorothy L. Sayers) |
#3
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A problem with a cd player
In article ,
Gaetan Mailloux wrote: My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Home recorded CDs ain't the same as commercial ones and some CD players simply can't cope with them. And re-recordable seem to be more prone to these problems than use once types. Think it's to do with the type of reflective layer. Strangely, very old ones seem ok - I have an early Philips dating from the '80s which does. Newish ones should be ok too. It's the inbetweens that can be a problem. -- *Learn from your parents' mistakes - use birth control. Dave Plowman London SW To e-mail, change noise into sound. |
#4
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A problem with a cd player
"Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs. Arfa |
#5
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A problem with a cd player
Gaetan Mailloux wrote:
Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, Try burning the CDs at a slower speed. -- Adrian C |
#6
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A problem with a cd player
"Arfa Daily" wrote in message
... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs. Arfa ************************************************** ****** Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). I agree - the OP should definitely clean the laser. Other maintenance, such as cleaning and lubricating other moving parts - rails, gears, motor spindles, etc, is also indicated. If after cleaning and maintenance issues are resolved the problem persists, another brand of CD-R's might help, or the laser may just be deteriorated to that point, especially if in a dusty and/or smoky environment. As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. |
#7
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A problem with a cd player
As you get further into a disc, its rotational speed falls to maintain
CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). |
#8
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A problem with a cd player
"William Sommerwerck" writes:
As you get further into a disc, its rotational speed falls to maintain CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). Nit picking. -- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. |
#9
Posted to sci.electronics.repair,sci.electronics.misc
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A problem with a cd player
"Mark Zacharias" ) writes:
"Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs. Arfa ************************************************** ****** Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). I agree - the OP should definitely clean the laser. Other maintenance, such as cleaning and lubricating other moving parts - rails, gears, motor spindles, etc, is also indicated. If after cleaning and maintenance issues are resolved the problem persists, another brand of CD-R's might help, or the laser may just be deteriorated to that point, especially if in a dusty and/or smoky environment. As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Hello Cleaning the laser lens and lubricating the mechanicals was the first thing I have done. I did try other cd-r brand but the problems still there. Maby the laser are at the end of his life ? Thank Bye Gaetan |
#10
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A problem with a cd player
Samuel M. Goldwasser wrote in message
... "William Sommerwerck" writes: As you get further into a disc, its rotational speed falls to maintain CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). Nit picking. -- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. Linguistically shouldn't it be "farther out of a disc", further for time, farther for distance. Any more nits? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#11
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A problem with a cd player
"Mark Zacharias" wrote in message ... "Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs. Arfa ************************************************** ****** Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). I agree - the OP should definitely clean the laser. Other maintenance, such as cleaning and lubricating other moving parts - rails, gears, motor spindles, etc, is also indicated. If after cleaning and maintenance issues are resolved the problem persists, another brand of CD-R's might help, or the laser may just be deteriorated to that point, especially if in a dusty and/or smoky environment. As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-( Still, the rest of what I said is valid. Arfa |
#12
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A problem with a cd player
"William Sommerwerck" wrote in message ... As you get further into a disc, its rotational speed falls to maintain CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). Yes indeed. See my reply to Mark. As far as "further into a disc" goes, we're just looking at it from two different angles. You are looking at it from the physical side, as indeed, the laser does read from the inside out. I was looking at it from the time angle - as in further into the disc's musical content. Arfa |
#13
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A problem with a cd player
"N_Cook" wrote in message ... Samuel M. Goldwasser wrote in message ... "William Sommerwerck" writes: As you get further into a disc, its rotational speed falls to maintain CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). Nit picking. -- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. Linguistically shouldn't it be "farther out of a disc", further for time, farther for distance. Any more nits? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ I was talking time, hence my using the word "further". See my reply to William. Arfa |
#14
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A problem with a cd player
"Arfa Daily" wrote in message
... "Mark Zacharias" wrote in message ... "Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs. Arfa ************************************************** ****** Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). I agree - the OP should definitely clean the laser. Other maintenance, such as cleaning and lubricating other moving parts - rails, gears, motor spindles, etc, is also indicated. If after cleaning and maintenance issues are resolved the problem persists, another brand of CD-R's might help, or the laser may just be deteriorated to that point, especially if in a dusty and/or smoky environment. As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-( Still, the rest of what I said is valid. Arfa I knew that you knew that. I was just foolin' around. mz |
#15
Posted to sci.electronics.repair,sci.electronics.misc
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A problem with a cd player
"Gaetan Mailloux" wrote in message
... "Mark Zacharias" ) writes: "Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-460 cd player. http://img101.imageshack.us/img101/4...60smallfy3.jpg Thank Bye Gaetan Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs. Arfa ************************************************** ****** Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc). I agree - the OP should definitely clean the laser. Other maintenance, such as cleaning and lubricating other moving parts - rails, gears, motor spindles, etc, is also indicated. If after cleaning and maintenance issues are resolved the problem persists, another brand of CD-R's might help, or the laser may just be deteriorated to that point, especially if in a dusty and/or smoky environment. As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Hello Cleaning the laser lens and lubricating the mechanicals was the first thing I have done. I did try other cd-r brand but the problems still there. Maby the laser are at the end of his life ? Thank Bye Gaetan If you have access to an oscilloscope, the HF "eye" pattern can be observed, and may be noisy. This would account for the deteriorated performance first on CD-R's. As previously noted, this is often the result of dust and smoke contamination. The finest particles get inside the laser, and settle on the turning mirror as a fine film. This diffuses the reflected laser light coming back off the disc before it can really be read. It is sometimes worthwhile to adjust the Focus Offset for maximum amplitude as viewed on the scope. If it makes a difference of about 20% or more, this may solve your problem, at least for the short term. Mark Z. Mark Z. |
#16
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A problem with a cd player
Perhaps because audio CD's are CLV... ;-) Mark Z. Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-( Still, the rest of what I said is valid. Arfa I knew that you knew that. I was just foolin' around. mz Yeah, I know that Mark. Dunno. The older I get, the more this nonsense seems to just fly out of my mouth (fingers) ... Perhaps I'm going down with some kind of early addle-brain. There's a prog on the telly next week about poor old Terry Pratchett. He first noticed something was wrong, when he kept typing spelleen misstaykes :-( I think that my problem is that I spend too much late-night time sitting in front of this idiot machine, instead of getting some sleep ... Arfa |
#17
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A problem with a cd player
"Arfa Daily" wrote in message
... Perhaps because audio CD's are CLV... ;-) Mark Z. Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-( Still, the rest of what I said is valid. Arfa I knew that you knew that. I was just foolin' around. mz Yeah, I know that Mark. Dunno. The older I get, the more this nonsense seems to just fly out of my mouth (fingers) ... Perhaps I'm going down with some kind of early addle-brain. There's a prog on the telly next week about poor old Terry Pratchett. He first noticed something was wrong, when he kept typing spelleen misstaykes :-( I think that my problem is that I spend too much late-night time sitting in front of this idiot machine, instead of getting some sleep ... Arfa Same problem here. Gets frustrating at times. I'll stop mid-sentence because I can't bring forth a noun to continue. Then after perhaps 2 or 3 seconds it comes and I finish the sentence. Short-term memory getting worse also, although in truth this has always been a weakness of mine. Still able to function at work though, so that's a blessing. My hearing is getting really bad also. With me it's early morning. I get up around 3:30 to 4:00 AM most days. Spend a lot of time perusing old analog meters etc on eBay. Added several to my collection lately, including an AVO 8 which I got interested in after finding you had one. It's a Mark 5 Nato model, on it's way from Germany as we speak. Not many AVO's in the U.S. it turns out... Added several Simpsons (the American answer to AVO?) lately as well. The guy at simpson260.com has offered to sell me his 9 remaining Simpsons. I don't think I can do that though, nowhere to put them! Mark Z. |
#18
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A problem with a cd player
Yeah, I know that Mark. Dunno. The older I get, the more this nonsense
seems to just fly out of my mouth (fingers)... Perhaps I'm going down with some kind of early addle-brain. There's a prog on the telly next week about poor old Terry Pratchett. He first noticed something was wrong, when he kept typing spelleen misstaykes :-( I think that my problem is that I spend too much late-night time sitting in front of this idiot machine, instead of getting some sleep... There's nothing wrong with you. As you get older, you're more likely to drop words or letters from your posts. And as time seems to pass faster, you have less time and inclination to think carefully about what you've written. |
#19
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A problem with a cd player
In article ,
Mark Zacharias wrote: Spend a lot of time perusing old analog meters etc on eBay. Added several to my collection lately, including an AVO 8 which I got interested in after finding you had one. It's a Mark 5 Nato model, on it's way from Germany as we speak. Not many AVO's in the U.S. it turns out... Those large AVOs were to be found pretty well everywhere even vaguely connected with electronics in the UK. Still available new up until recently - at about $1000. My original one got stolen many years ago - and like many others I just used a DVM instead. But always wanted another - and got a perfect condition one off Ebay a few years ago. Nothing else quite matches the tactile switches. ;-) And of course if working to old service sheets, voltage measurements were near always made on one so allowed for the loading. -- *Horn broken. - Watch for finger. Dave Plowman London SW To e-mail, change noise into sound. |
#20
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A problem with a cd player
"Meat Plow" wrote in message ... On Fri, 30 Jan 2009 05:47:47 -0600, "Mark Zacharias" wrote: "Arfa Daily" wrote in message ... Perhaps because audio CD's are CLV... ;-) Mark Z. Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-( Still, the rest of what I said is valid. Arfa I knew that you knew that. I was just foolin' around. mz Yeah, I know that Mark. Dunno. The older I get, the more this nonsense seems to just fly out of my mouth (fingers) ... Perhaps I'm going down with some kind of early addle-brain. There's a prog on the telly next week about poor old Terry Pratchett. He first noticed something was wrong, when he kept typing spelleen misstaykes :-( I think that my problem is that I spend too much late-night time sitting in front of this idiot machine, instead of getting some sleep ... Arfa Same problem here. Gets frustrating at times. I'll stop mid-sentence because I can't bring forth a noun to continue. Then after perhaps 2 or 3 seconds it comes and I finish the sentence. Short-term memory getting worse also, although in truth this has always been a weakness of mine. Still able to function at work though, so that's a blessing. My hearing is getting really bad also. With me it's early morning. I get up around 3:30 to 4:00 AM most days. Spend a lot of time perusing old analog meters etc on eBay. Added several to my collection lately, including an AVO 8 which I got interested in after finding you had one. It's a Mark 5 Nato model, on it's way from Germany as we speak. Not many AVO's in the U.S. it turns out... Added several Simpsons (the American answer to AVO?) lately as well. The guy at simpson260.com has offered to sell me his 9 remaining Simpsons. I don't think I can do that though, nowhere to put them! Mark Z. Old age sucks. Big time for sure. Thirty years ago, I thought I was immortal, and could keep going for two or more days at a time without sleep. I just couldn't figure how people could degenerate into the old farts that they did. Now I am one, and I look at my daughter looking at me thinking "I just can't figure ... " Sigh ... :-\ Arfa |
#21
Posted to sci.electronics.repair,sci.electronics.misc
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A problem with a cd player
"Mark Zacharias" ) writes:
"Gaetan Mailloux" wrote in message ... "Mark Zacharias" ) writes: "Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-46 As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Hello Cleaning the laser lens and lubricating the mechanicals was the first thing I have done. I did try other cd-r brand but the problems still there. Maby the laser are at the end of his life ? Thank Bye Gaetan If you have access to an oscilloscope, the HF "eye" pattern can be observed, and may be noisy. This would account for the deteriorated performance first on CD-R's. As previously noted, this is often the result of dust and smoke contamination. The finest particles get inside the laser, and settle on the turning mirror as a fine film. This diffuses the reflected laser light coming back off the disc before it can really be read. It is sometimes worthwhile to adjust the Focus Offset for maximum amplitude as viewed on the scope. If it makes a difference of about 20% or more, this may solve your problem, at least for the short term. Mark Z. Mark Z. Hello I have an old Telequipment scope who goes up to 1 mhz, it should do the job. I've look on the main pcb and there is 4 trimpot; T.BAL , F.BAL , FEOF , TEOF Wich one are for adjusting the Focus Offset ? Thank a lot Gaetan |
#22
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A problem with a cd player
"Gaetan Mailloux" wrote in message
... "Mark Zacharias" ) writes: "Gaetan Mailloux" wrote in message ... "Mark Zacharias" ) writes: "Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-46 As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Hello Cleaning the laser lens and lubricating the mechanicals was the first thing I have done. I did try other cd-r brand but the problems still there. Maby the laser are at the end of his life ? Thank Bye Gaetan If you have access to an oscilloscope, the HF "eye" pattern can be observed, and may be noisy. This would account for the deteriorated performance first on CD-R's. As previously noted, this is often the result of dust and smoke contamination. The finest particles get inside the laser, and settle on the turning mirror as a fine film. This diffuses the reflected laser light coming back off the disc before it can really be read. It is sometimes worthwhile to adjust the Focus Offset for maximum amplitude as viewed on the scope. If it makes a difference of about 20% or more, this may solve your problem, at least for the short term. Mark Z. Mark Z. Hello I have an old Telequipment scope who goes up to 1 mhz, it should do the job. I've look on the main pcb and there is 4 trimpot; T.BAL , F.BAL , FEOF , TEOF Wich one are for adjusting the Focus Offset ? Thank a lot Gaetan FEOF should be the one, but a 1 meg scope won't really get it. You can adjust for maximum envelope size, which probably is good enough, but you can't look at the diamond shaped center area of the expanded "eye" pattern as viewed on a 30mHz or higher scope. Sometimes a x10 probe is required, but in my experience it is rare for a direct probe to load down this measurement. You can "Google CD eye pattern" and see what I'm talking about. Mark Z. |
#23
Posted to sci.electronics.repair,sci.electronics.misc
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A problem with a cd player
If you have access to an oscilloscope, the HF "eye" pattern can be observed, and may be noisy. This would account for the deteriorated performance first on CD-R's. As previously noted, this is often the result of dust and smoke contamination. The finest particles get inside the laser, and settle on the turning mirror as a fine film. This diffuses the reflected laser light coming back off the disc before it can really be read. It is sometimes worthwhile to adjust the Focus Offset for maximum amplitude as viewed on the scope. If it makes a difference of about 20% or more, this may solve your problem, at least for the short term. Mark Z. Mark Z. Hello I have an old Telequipment scope who goes up to 1 mhz, it should do the job. I've look on the main pcb and there is 4 trimpot; T.BAL , F.BAL , FEOF , TEOF Wich one are for adjusting the Focus Offset ? Thank a lot Gaetan FEOF should be the one, but a 1 meg scope won't really get it. You can adjust for maximum envelope size, which probably is good enough, but you can't look at the diamond shaped center area of the expanded "eye" pattern as viewed on a 30mHz or higher scope. Sometimes a x10 probe is required, but in my experience it is rare for a direct probe to load down this measurement. You can "Google CD eye pattern" and see what I'm talking about. Mark Z. All that Mark says, but before you start, CAREFULLY mark the EXACT positions of the pots before attempting adjustment. If you do adjust more than one of them (the temptation *will* be there - trust me !!) and you do not have the proper bandwidth 'scope, and the experience to know exactly what you are adjusting and why, it is staggeringly easy to get those pots to a point where nothing will be read at all, often with just a few degrees mispositioning of a couple of them. Re-finding the correct places to get it going again, can then be a most frustrating excercise ... Arfa |
#24
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A problem with a cd player
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#25
Posted to sci.electronics.repair,sci.electronics.misc
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A problem with a cd player
"Mark Zacharias" ) writes:
"Gaetan Mailloux" wrote in message ... "Mark Zacharias" ) writes: "Gaetan Mailloux" wrote in message ... "Mark Zacharias" ) writes: "Arfa Daily" wrote in message ... "Gaetan Mailloux" wrote in message ... Hello A friend of mine do have a kenwood DP-460 cd player with a cd playing problem. My friend was sure that the laser was burned, but I decide to test his Kenwood cd player, wen I use commercial music cd it work perfect, but wen I use burned cd-r music, this Kenwood cd player can not play more than 7 track, after 7 track it do jerky sound with the music, it look like it can not follow those track. Any hints of what could be the problems ? Here is a link to a part of the schematic of the kenwood DP-46 As you get further into a disc, its rotational speed falls to maintain CAV. Perhaps because audio CD's are CLV... ;-) Mark Z. Hello Cleaning the laser lens and lubricating the mechanicals was the first thing I have done. I did try other cd-r brand but the problems still there. Maby the laser are at the end of his life ? Thank Bye Gaetan If you have access to an oscilloscope, the HF "eye" pattern can be observed, and may be noisy. This would account for the deteriorated performance first on CD-R's. As previously noted, this is often the result of dust and smoke contamination. The finest particles get inside the laser, and settle on the turning mirror as a fine film. This diffuses the reflected laser light coming back off the disc before it can really be read. It is sometimes worthwhile to adjust the Focus Offset for maximum amplitude as viewed on the scope. If it makes a difference of about 20% or more, this may solve your problem, at least for the short term. Mark Z. Mark Z. Hello I have an old Telequipment scope who goes up to 1 mhz, it should do the job. I've look on the main pcb and there is 4 trimpot; T.BAL , F.BAL , FEOF , TEOF Wich one are for adjusting the Focus Offset ? Thank a lot Gaetan FEOF should be the one, but a 1 meg scope won't really get it. You can adjust for maximum envelope size, which probably is good enough, but you can't look at the diamond shaped center area of the expanded "eye" pattern as viewed on a 30mHz or higher scope. Sometimes a x10 probe is required, but in my experience it is rare for a direct probe to load down this measurement. You can "Google CD eye pattern" and see what I'm talking about. Mark Z. Hello I will borrow a Sencore SC61 scope to a friend who do not use it, maby I will buy it anyway since it is doing nothing in his basement. Btw, what would be T.BAL , F.BAL, TEOF ? Thank for your help Bye Gaetan |
#26
Posted to sci.electronics.repair,sci.electronics.misc
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A problem with a cd player
Hello I will borrow a Sencore SC61 scope to a friend who do not use it, maby I will buy it anyway since it is doing nothing in his basement. Btw, what would be T.BAL , F.BAL, TEOF ? Thank for your help Bye Gaetan T.B(AL) is tracking balance. Sometimes also known as E-F BAL (named for the designations of the two photodiodes, "E" and "F" in the pickup, which are responsible for generating the tracking control signal). It is required in order to remove unwanted positional offsets of the lens which would otherwise be caused by imbalances in the tracking servo photodiodes in the pickup, and the following opamp in the tracking servo processor. F.B(AL) is focus balance. Does the same for the focus servo circuitry as TBAL does for the tracking. TE(OF) is tracking error offset. Allows the electrical zero point of the tracking servo to be set to match the lens suspension mechanical zero. It is needed to offset mechanical errors in the construction of the laser, and electrical servo errors which may creep in as a result of imperfect opamps etc in the servo amplifier. FE(OF) would be the same thing for the focus servo, and is needed to correct for such things as an error in the turntable height, and similar servo electrical errors. You may find a pot called PLL on some players. The setting of this is *extremely* critical to data recovery from the disc, and requires an accurate frequency counter to set it up. NEVER adjust this pot randomly, even if you think that you have marked its original position perfectly. It is rare to find any of these adjustments present, in modern players. The servo processor ICs are these days capable of performing an analysis of the signal, and introducing and storing appropriate correctional offsets. Other pots which may also be encountered are T.G(AIN) and F.G(AIN). These set the operational gains of the tracking and focus servo loops. They are often to still be found in modern players. Adjusting these up slightly, can often improve a player with marginal performance, but if set too high, particularly in the case of the focus servo, will result in the lens making a mechanical 'hissing' noise, particularly on a marked or scuffed disc. Finally, there is always a pot on the laser which sets its output power. With a few notable exceptions such as Pioneer, this pot is sealed and MUST NOT be adjusted. Even a small overdrive of the laser diode, can result in its partial, or even complete destruction. Arfa |
#28
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A problem with a cd player
In article ,
Meat Plow wrote: I hate it when going through the checkout at the grocer the hot cashier in her mid 20's calls me Sir. But if I lived in the UK I guess that would be a compliment right :-) Even a grunt would be nice. -- *Sorry, I don't date outside my species. Dave Plowman London SW To e-mail, change noise into sound. |
#29
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A problem with a cd player
"Dave Plowman (News)" wrote in message ... In article , Meat Plow wrote: I hate it when going through the checkout at the grocer the hot cashier in her mid 20's calls me Sir. But if I lived in the UK I guess that would be a compliment right :-) Even a grunt would be nice. Go to Waitrose, Dave. The staff in there are everything that you would ever want them to be, and then some ... I actually don't mind being called "sir". It shows that if nothing else, my age has won me at least a modicum of respect from the next generation down ! :-) Arfa -- *Sorry, I don't date outside my species. Dave Plowman London SW To e-mail, change noise into sound. |
#30
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A problem with a cd player
"Meat Plow" wrote in message ... On Mon, 2 Feb 2009 01:39:47 -0000, "Arfa Daily" wrote: "Dave Plowman (News)" wrote in message ... In article , Meat Plow wrote: I hate it when going through the checkout at the grocer the hot cashier in her mid 20's calls me Sir. But if I lived in the UK I guess that would be a compliment right :-) Even a grunt would be nice. Go to Waitrose, Dave. The staff in there are everything that you would ever want them to be, and then some ... I actually don't mind being called "sir". It shows that if nothing else, my age has won me at least a modicum of respect from the next generation down ! :-) Arfa Sir Arfa Daily. Has a good ring to it ;-) If you're familiar with the TV series from the eighties which spawned it, even more so !! Interestingly, a 'brought up to date' remake of it starts on British TV this Wednesday evening. Big boots to fill for all concerned, but in the write-ups, the cast say that they are very clear about that, so we'll givit a go ... Arfa |
#31
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A problem with a cd player
Arfa Daily wrote: Depends how you define "young", I guess. I've not yet reached decrepit, but certainly old enough to be waking up in the night for a bathroom stop, and waking up in the morning feeling worse than I did when I went to bed ... Just be glad you're still waking up before you go to the bathroom. That's when they pick out a nursing home for you, and hide anything sharp or hot. ;-) -- http://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy. |
#32
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A problem with a cd player
"Samuel M. Goldwasser" wrote: "William Sommerwerck" writes: As you get further into a disc, its rotational speed falls to maintain CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). Nit picking. If no one picked nits, we'd be buried in the lousy things! -- http://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy. |
#33
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A problem with a cd player
In article ,
says... "krw" wrote in message t... In article , says... "Meat Plow" wrote in message ... On Fri, 30 Jan 2009 05:47:47 -0600, "Mark Zacharias" wrote: "Arfa Daily" wrote in message ... Perhaps because audio CD's are CLV... ;-) Mark Z. Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-( Still, the rest of what I said is valid. Arfa I knew that you knew that. I was just foolin' around. mz Yeah, I know that Mark. Dunno. The older I get, the more this nonsense seems to just fly out of my mouth (fingers) ... Perhaps I'm going down with some kind of early addle-brain. There's a prog on the telly next week about poor old Terry Pratchett. He first noticed something was wrong, when he kept typing spelleen misstaykes :-( I think that my problem is that I spend too much late-night time sitting in front of this idiot machine, instead of getting some sleep ... Arfa Same problem here. Gets frustrating at times. I'll stop mid-sentence because I can't bring forth a noun to continue. Then after perhaps 2 or 3 seconds it comes and I finish the sentence. Short-term memory getting worse also, although in truth this has always been a weakness of mine. Still able to function at work though, so that's a blessing. My hearing is getting really bad also. With me it's early morning. I get up around 3:30 to 4:00 AM most days. Spend a lot of time perusing old analog meters etc on eBay. Added several to my collection lately, including an AVO 8 which I got interested in after finding you had one. It's a Mark 5 Nato model, on it's way from Germany as we speak. Not many AVO's in the U.S. it turns out... Added several Simpsons (the American answer to AVO?) lately as well. The guy at simpson260.com has offered to sell me his 9 remaining Simpsons. I don't think I can do that though, nowhere to put them! Mark Z. Old age sucks. Big time for sure. Thirty years ago, I thought I was immortal, and could keep going for two or more days at a time without sleep. I just couldn't figure how people could degenerate into the old farts that they did. Now I am one, and I look at my daughter looking at me thinking "I just can't figure ... " You're still young. Don't worry, as your daughter gets older, you'll get wiser. ;-) Depends how you define "young", I guess. If your daughter still thinks you're dumb, you're not old. As you (she) ages, amazingly, you'll get a lot smarter. I've not yet reached decrepit, but certainly old enough to be waking up in the night for a bathroom stop, and As long as you're still waking up... waking up in the morning feeling worse than I did when I went to bed ... d;~} I grew out of that a while back, except when the RA is doing its thing. Then mornings are a pain everywhere (but my butt). |
#34
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A problem with a cd player
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#35
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A problem with a cd player
krw wrote: In article , says... "Samuel M. Goldwasser" wrote: "William Sommerwerck" writes: As you get further into a disc, its rotational speed falls to maintain CAV. I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV. Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out). Nit picking. If no one picked nits, we'd be buried in the lousy things! And there is nothing lousier than nits. Except lousy donkeys. -- http://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy. |
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